'I've always kept very fit. I've never been one to get ill. Yet something seemingly so small was causing a great deal of trouble. I couldn't even shake hands properly.'

A visit to his GP resulted in a swift diagnosis. Sir John had Dupuytren's contracture, which causes fingers to bend into the palm. Lady Thatcher is a sufferer. Actor Bill Nighy has been treated for it, as was President Ronald Reagan.

Dr John White, a consultant hand and upper limb surgeon at Queens College Hospital, Romford, and the BMI The Garden Hospital in London, says the condition occurs when small growths or lumps of tissue, caused by abnormality in the cells, appear in deep connective tissue in the palm: 'Over time, the nodules can contract until it is difficult to extend fingers. Untreated these will become fixed in a permanently bent position.'

Dr White says up to one in five men over 60 are sufferers, and a similar proportion of women in their 80s.

Lady Thatcher is also a sufferer of Dupuytren's contracture

There is a genetic link in about 70 per cent of cases, but Dr White says the further causes are unknown.

'We don't know what triggers cells to become overactive, but there is some evidence to suggest a hand injury could activate it.

'That men suffer it earlier than women suggests the female hormone oestrogen inhibits the process. Alcohol, smoking and conditions such as diabetes may raise risk too.'

The NHS carries out about 12,000 operations to treat the condition each year. Sir John decided to wait until surgery was absolutely necessary. He was referred to an NHS clinic at BMI The Garden Hospital.

In mild cases doctors may opt for a fasciotomy, where palm tissue is
cut to release tension. But as Sir John's case was quite severe, his
surgeon decided on a dermofasciectomy, which involves removing skin and
diseased fibrous tissue, but preserving nerves and blood vessels,
followed by a skin graft.

'It sounded straightforward,
particularly since I was told it could be done without general
anaesthetic. And I was driven by the fact I wanted to go skiing a few
months later.'

Last November, in a three-hour operation under
local anaesthetic, surgeons cut away tissue in an area the size of a
twopence piece.

A skin graft from Sir John's upper arm was stitched over
the wound and his fingers were set in individual removable plaster
casts.

After three days, the finger splints were taken off
several times a day to allow him to do stretching exercises. Within two
months his fingers were straight.

'It was like getting a new hand,' says
Sir John.

The finger splints were removed after four weeks, though they have to
be worn at night for six months. There is a thin scar on Sir John's
palm.

'I heard how Lady Thatcher handled similar surgery,' he
says.

'She got chatting to an adviser and asked how he was. "Oh not
good," he said. "I've just had an operation for this condition called
Dupuytren's contracture and it's very painful."

' "Oh, you are a wimp," she replied. I've no intention of being one either. Particularly now I can button up a shirt again.'